With respect to other certificates, it has usually been designated as a second-generation certificate.

The certificate is issued on the basis of building sustainability assessment, the word sustainability being used here in its much wider meaning, which differs from its common meaning in green building, but it is in accordance with the guidelines of the European Union.

It represents a holistic approach which:

evaluates all main aspects of sustainability,

as well as the total building performance rather than just individual measures

assessment is based on the entire life cycle of a building (from raw material extraction and production, through construction and use, to decomposition, recycling or disposal)

Apart from environmental and socio-cultural quality, which green building implies in its narrower meaning, this certification system also provides for the assessment of the economic and technical quality of a building, as well as the quality of the design, construction and monitoring processes. Site quality is evaluated separately (floods, landslides, transport, pollution, etc.).

Environmental quality

When the dramatic increase in world population as well as the concentration of city population is taken into account, it becomes more than evident that the impact which buildings have on the environment is significant (it is estimated that by 2050, 70% of the world population will live in cities). As a result, construction industry is already responsible for 40-50% of raw material exploitation, 30-40% of energy consumption, 33% of carbon dioxide emissions, 25% of forest exploitation and 17% of water consumption.

In the environmental quality assessment according to the DGNB method, the LCA (Life Cycle Assessment) calculation is crucial. LCA is a systematic calculation of the total environmental impact of a building throughout its entire life cycle and it measures the extent to which a building is responsible for the emissions defined under the Kyoto Protocol, as well as for energy, water and raw materials consumption.

This type of calculation became possible once the international EPD system (Environmental Product Declaration, ISO 14025, EN 15804) became standardized. It is a system of building product declaration which provides information about the environmental impact of a building over its entire life cycle.

Criteria evaluated include avoidance of materials which are harmful to the immediate environment, choice of sites which were already used or which are polluted, as well as purchase of wood from a local company in line with sustainability standards of the Forest Stewardship Council (FSC).

Economic quality

Green building is based on careful use of resources, which also includes financial resources.

According to the DGBN assessment system, the building’s total life-cycle costs (LCC) must be calculated. It is a tool for the optimisation of the costs of a building; that is, for calculation of costs incurred throughout the building’s entire life cycle, which include:

construction,

energy sources used over time,

maintenance and periodic costs,

water consumption over time;

financing costs.

Consumption of energy sources over time (data also used for assessment of environmental quality) is calculated by the LCEM (Life Cycle Energy Modelling) method.

Except for life-cycle costs, space efficiency, flexibility and adaptability are also evaluated.

Socio-cultural and functional quality

The next category consists of about fifteen criteria. These are: indoor air quality, presence of poisonous and hazardous substances, thermal comfort: temperature asymmetries during the heating and cooling periods, air circulation speed, indoor acoustic conditions, availability of daylight and open view to the outside, quality of natural and artificial light.

Evaluated criteria also include accessibility for disabled persons, public access, quality of outdoor areas, integration of art in the building, facilities for bicycles and hybrid vehicles, etc.

The possibility of easy cleaning and maintenance as well as deconstruction and recycling are also evaluated.

Process quality

The quality of design, tender and monitoring processes is evaluated. For example, elements that are evaluated as positive are implementation of a public architectural tendering procedure, formation of an interdisciplinary team of experts at an early stage of the project, assessment of the quality of the bill of quantities, organisation of construction site, etc.

Total score for each category is finally calculated in percentages, expressing the difference between the typical building practice in line with the applicable minimum requirements (0%) and the best building practices used at the moment (100%). Good building practice represents the reference value (50%). Depending on the results, a bronze, silver or gold certificate is awarded.

The DGNB method is based on current European norms and standards. Calculations important for the DGNB method – LCA (Life Cycle Assessment) and LCC (Life Cycle Costing) – have also been developed on the basis of EU guidelines and are gradually being implemented into European building regulations.

In conclusion, we can say that this certificate, apart from being an internationally approved and recognised quality identification, also points to the direction in which European building practices will continue to develop.